My flat roof ponds water after rain. Is that a problem?

Standing water that is still there a day or two later is worth addressing. It usually means the slope or the drainage is wrong rather than the membrane, and adding a new membrane over the same pitch will not fix it.

Can a flat section be repaired, or does it all need replacing?

Membrane repairs are routine — punctures and seam failures patch well. If the membrane has gone brittle across the whole area, or there is trapped moisture in the insulation below, replacement is the honest answer.

Flat roofing

Very few houses around here are flat-roofed, but a great many have a flat section — and that section is where the leaks start.

Where the low slope actually is

Porch roofs, the tops of dormers, the flat behind a parapet, a rear extension added in the 1970s. These runs are too shallow for shingle to shed water reliably, and when someone has shingled them anyway, they leak.

They need a membrane, and they need the transition between the membrane and the pitched roof above handled properly. That transition is the single most common failure point we are called out to.

EPDM and TPO

EPDM is the black rubber membrane most people picture. It is well proven, it handles the local freeze-thaw cycle, and it is straightforward to repair years later.

TPO is a single-ply membrane, usually white, and its reflectivity keeps the surface cooler in summer — which matters if there is living space directly underneath. Both are good systems. Which one suits your roof depends on what is beneath it, what it connects to, and whether anyone will see it.

EPDM rubber: proven, repairable, the common choice
TPO single-ply: reflective, cooler over living space

Common questions

My flat roof ponds water after rain. Is that a problem?: Standing water that is still there a day or two later is worth addressing. It usually means the slope or the drainage is wrong rather than the membrane, and adding a new membrane over the same pitch will not fix it.
Can a flat section be repaired, or does it all need replacing?: Membrane repairs are routine — punctures and seam failures patch well. If the membrane has gone brittle across the whole area, or there is trapped moisture in the insulation below, replacement is the honest answer.

Need flat roofing?

Tell us what the roof is doing and we will come and look at it. Free estimate, no obligation, and a straight answer about what the job actually needs.

$500 off a complete roof installation

Applied to your estimate for a full roof replacement.
$100 off any roof repair

Applied to your estimate for repair work of any size.
Offers cannot be combined. Not valid on work already completed.

Call us: (617) 244-9901
Email: residential@newtonroofing.com
Office hours: Mon–Sat, 7am–7pm

Get your free estimate

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